Attempts are increasingly being made to limit or eliminate the use of chemical preservatives in fluids, particularly in the medical field. Consequently, it is important for a dispenser device to provide the greatest possible degree of sealing (against liquids, gases, bacteria) between the outside and the inside of the device or the reservoir, i.e. all along the path traveled by the fluid so as to prevent bacteria from developing and contaminating the fluid.
Such devices are often referred to as “preservative-free” devices. They may be provided with a dispenser endpiece that is fitted on the pump and that includes a check valve arranged immediately in front of the fluid dispenser orifice to prevent bacteria developing in the dispenser endpiece. By way of example, one such endpiece is described in publication FR 2 887 232.